kernel_optimize_test/arch/mips
Maciej W. Rozycki 17f3c64f70 MIPS: Malta: Do not byte-swap accesses to the CBUS UART
commit 9a936d6c3d3d6c33ecbadf72dccdb567b5cd3c72 upstream.

Correct big-endian accesses to the CBUS UART, a Malta on-board discrete
TI16C550C part wired directly to the system controller's device bus, and
do not use byte swapping with the 32-bit accesses to the device.

The CBUS is used for devices such as the boot flash memory needed early
on in system bootstrap even before PCI has been initialised.  Therefore
it uses the system controller's device bus, which follows the endianness
set with the CPU, which means no byte-swapping is ever required for data
accesses to CBUS, unlike with PCI.

The CBUS UART uses the UPIO_MEM32 access method, that is the `readl' and
`writel' MMIO accessors, which on the MIPS platform imply byte-swapping
with PCI systems.  Consequently the wrong byte lane is accessed with the
big-endian configuration and the UART is not correctly accessed.

As it happens the UPIO_MEM32BE access method makes use of the `ioread32'
and `iowrite32' MMIO accessors, which still use `readl' and `writel'
respectively, however they byte-swap data passed, effectively cancelling
swapping done with the accessors themselves and making it suitable for
the CBUS UART.

Make the CBUS UART switch between UPIO_MEM32 and UPIO_MEM32BE then,
based on the endianness selected.  With this change in place the device
is correctly recognised with big-endian Malta at boot, along with the
Super I/O devices behind PCI:

Serial: 8250/16550 driver, 5 ports, IRQ sharing enabled
printk: console [ttyS0] disabled
serial8250.0: ttyS0 at I/O 0x3f8 (irq = 4, base_baud = 115200) is a 16550A
printk: console [ttyS0] enabled
printk: bootconsole [uart8250] disabled
serial8250.0: ttyS1 at I/O 0x2f8 (irq = 3, base_baud = 115200) is a 16550A
serial8250.0: ttyS2 at MMIO 0x1f000900 (irq = 20, base_baud = 230400) is a 16550A

Fixes: e7c4782f92 ("[MIPS] Put an end to <asm/serial.h>'s long and annyoing existence")
Cc: stable@vger.kernel.org # v2.6.23+
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Maciej W. Rozycki <macro@orcam.me.uk>
Link: https://lore.kernel.org/r/alpine.DEB.2.21.2106260524430.37803@angie.orcam.me.uk
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-08-12 13:22:15 +02:00
..
alchemy MIPS: alchemy: xxs1500: add gpio-au1000.h header file 2021-06-03 09:00:50 +02:00
ar7 MIPS: replace add_memory_region with memblock 2020-10-12 12:01:36 +02:00
ath25 MIPS: replace add_memory_region with memblock 2020-10-12 12:01:36 +02:00
ath79 MIPS: ath79: Remove unused include <asm/mips_machine.h> 2020-07-28 10:20:44 +02:00
bcm47xx MIPS: BCM47XX: fix kconfig dependency bug for BCM47XX_BCMA 2020-12-30 11:53:09 +01:00
bcm63xx MIPS: replace add_memory_region with memblock 2020-10-12 12:01:36 +02:00
bmips dma-direct: rename and cleanup __phys_to_dma 2020-09-11 09:14:43 +02:00
boot mips: disable branch profiling in boot/decompress.o 2021-07-20 16:05:58 +02:00
cavium-octeon Revert "MIPS: Octeon: Remove special handling of CONFIG_MIPS_ELF_APPENDED_DTB=y" 2021-03-04 11:38:26 +01:00
cobalt MIPS: replace add_memory_region with memblock 2020-10-12 12:01:36 +02:00
configs MIPS: Loongson64: Select SMP in Kconfig to avoid build error 2020-10-12 11:22:40 +02:00
crypto crypto: poly1305 - fix poly1305_core_setkey() declaration 2021-05-14 09:50:13 +02:00
dec MIPS: DEC: Restore bootmem reservation for firmware working memory area 2020-10-14 23:57:57 +02:00
fw MIPS: replace add_memory_region with memblock 2020-10-12 12:01:36 +02:00
generic MIPS: generic: Update node names to avoid unit addresses 2021-06-30 08:47:16 -04:00
include MIPS: check return value of pgtable_pmd_page_ctor 2021-08-12 13:22:07 +02:00
ingenic MIPS: jz4740: Rename jz4740 folders to ingenic 2020-09-18 16:35:05 +02:00
jazz dma-mapping: merge <linux/dma-noncoherent.h> into <linux/dma-map-ops.h> 2020-10-06 07:07:06 +02:00
kernel MIPS: cpu-probe: Fix FPU detection on Ingenic JZ4760(B) 2021-07-19 09:44:44 +02:00
kvm KVM: MIPS: clean up redundant kvm_run parameters in assembly 2020-09-28 07:57:21 -04:00
lantiq MIPS: lantiq: Explicitly compare LTQ_EBU_PCC_ISTAT against 0 2021-03-04 11:37:38 +01:00
lib MIPS: Fix kernel hang under FUNCTION_GRAPH_TRACER and PREEMPT_TRACER 2021-06-16 12:01:37 +02:00
loongson2ef MIPS updates for v5.10: 2020-10-16 12:40:55 -07:00
loongson32 MIPS: replace add_memory_region with memblock 2020-10-12 12:01:36 +02:00
loongson64 MIPS: loongsoon64: Reserve memory below starting pfn to prevent Oops 2021-07-19 09:44:55 +02:00
math-emu MIPS: Use fallthrough for arch/mips 2020-05-07 11:55:47 +02:00
mm MIPS: c-r4k: Fix section mismatch for loongson2_sc_init 2021-03-04 11:37:38 +01:00
mti-malta MIPS: Malta: Do not byte-swap accesses to the CBUS UART 2021-08-12 13:22:15 +02:00
net bpf: Introduce BPF nospec instruction for mitigating Spectre v4 2021-08-04 12:46:44 +02:00
netlogic MIPS updates for v5.10: 2020-10-16 12:40:55 -07:00
oprofile mips/oprofile: Fix fallthrough placement 2020-08-22 09:23:15 +02:00
pci MIPS: pci-legacy: stop using of_pci_range_to_resource 2021-05-14 09:50:39 +02:00
pic32 MIPS: Only include the platform file needed 2020-05-13 00:17:18 +02:00
pistachio MIPS: Fix exception handler memcpy() 2020-05-24 09:15:54 +02:00
power mips: check for dsp presence only once before save/restore 2019-10-07 10:58:53 -07:00
ralink MIPS: ralink: export rt_sysc_membase for rt2880_wdt.c 2021-06-03 09:00:50 +02:00
rb532 MIPS: replace add_memory_region with memblock 2020-10-12 12:01:36 +02:00
sgi-ip22 MIPS: Only include the platform file needed 2020-05-13 00:17:18 +02:00
sgi-ip27 mm/sparse: cleanup the code surrounding memory_present() 2020-08-07 11:33:27 -07:00
sgi-ip30 MIPS: SGI-IP30: Move irq bits to better header files 2020-09-21 22:15:49 +02:00
sgi-ip32 MIPS updates for v5.10: 2020-10-16 12:40:55 -07:00
sibyte MIPS: replace add_memory_region with memblock 2020-10-12 12:01:36 +02:00
sni MIPS: SNI: Fix spurious interrupts 2020-09-16 22:40:58 +02:00
tools MIPS: tools: Fix resource leak in elf-entry.c 2020-05-24 09:29:48 +02:00
txx9 MIPS: replace add_memory_region with memblock 2020-10-12 12:01:36 +02:00
vdso MIPS: VDSO: Use CLANG_FLAGS instead of filtering out '--target=' 2021-03-04 11:38:26 +01:00
vr41xx MIPS: Fix builds for VR41xx platforms 2020-05-15 09:09:58 +02:00
Kbuild MIPS: Fix "make clean" error due to recent changes 2020-05-13 13:20:22 +02:00
Kbuild.platforms MIPS: generic: Add support for Ingenic SoCs 2020-09-18 16:33:59 +02:00
Kconfig MIPS: ingenic: Select CPU_SUPPORTS_CPUFREQ && MIPS_EXTERNAL_TIMER 2021-07-19 09:44:44 +02:00
Kconfig.debug mips: Add CPS_NS16550_WIDTH config 2020-05-22 09:12:52 +02:00
Makefile mips: Fix non-POSIX regexp 2021-08-12 13:22:07 +02:00
Makefile.postlink MIPS: fix indentation of the 'RELOCS' message 2020-01-20 15:37:30 -08:00